1. Field of the Invention
The present invention relates to aqueous cleaning compositions and methods of cleaning surfaces using aqueous cleaning compositions.
2. Description of the Related Art
All environments used by human beings need to be cleaned. Such environments may be categorised as domestic, public or industrial and may include homes, healthcare centres, schools, leisure centres, restaurants, public buildings, work places and industrial settings. Aqueous cleaning compositions are commercially important products and enjoy a wide field of utility in assisting in the removal of dirt and grime from surfaces within these environments.
A wide range of aqueous cleaning compositions have been developed in the art. Such cleaning compositions have a biocidal activity and aim to kill 99.9% of bacteria present in the domestic, public or industrial environment. Disinfection of a surface in the household therefore leaves an environment almost free of bacteria. As set out in Germicidal and Detergent Sanitising Action of Disinfectants, Official Methods of Analysis of the Association of Official Analytical Chemists, paragraph 960.09 and applicable sections, 15th Edition, 1990, a sanitizer should provide a 99.999% reduction (5-log order reduction) within 30 seconds at room temperature, 25±2° C., against several test organisms.
A problem associated with biocidal cleaning compositions in the prior art is that as soon as a surface has been cleaned, the surface is almost free of bacteria. If a pathogenic bacterium were to land on the clean surface, this pathogenic bacterium would experience no competition and would soon colonise to take up the available space. Human beings therefore aim to be too clean. Further, by cleaning surfaces with a biocidal cleaning composition, this effectively forces pathogenic bacteria to evolve and develop immunity to various antibiotic treatments. These resistant strains are difficult to deal with.
In an article by Andrew A. Pollack entitled “A Rising Hospital Threat”, in the New York Times dated 27 Feb. 2010, a Gram-negative drug resistant bacterium, known as Acinetobacter baumannii, was discussed. There are no known drugs that have been effective in fighting the Gram-negative bacteria, although there are two older antibiotics that were developed in the 1940s that are currently being used in the battle. Those two are colistin and polymyxin B, but they can cause severe kidney and nerve damage.
Further, a survey based on a one-day snapshot taken on 24 Nov. 2008 at 648 hospitals in 47 states in the United States found that more than 1% of U.S. hospital patients are infected with Clostridium difficile (C. diff). The Association for Professionals in Infection Control and Epidemiology, a national professional society whose members include doctors, nurses and epidemiologists commissioned the survey. The survey determined that 13 out of every 1,000 hospitalized patients tested positive for C. diff. 
The survey also reports that use of a bleach solution to clean rooms of infected patients is important in trying to prevent the spread of the disease in the hospital and that proper hand washing is essential. The survey reports that the spores are not always killed by alcohol-based disinfectant gels. Therefore, even when using biocidal compositions, a small number of spores of pathogenic bacteria may remain which would quickly colonise.
There is therefore a need for an alternative composition and method for cleaning surfaces in the domestic, public and industrial environment.
It is known to use bacteria within cleaning products. Bacteria are already used in drain maintenance to avoid fat related drain blockages and maintain the condition of drains. This drain maintenance process involves a natural bio-fluid which is a blend of Hazard Group 1 Bacillus spores and bio-degradable surfactants. This biofluid is currently provided by Cleveland Biotech Ltd under the trade name GreaseBeta®. Typical applications include the drains serving pot-wash sinks and rotisserie oven condensate discharge lines.
Bacteria are already used in cleaning products for toilets and urinals, wherein the product is designed to dissolve and prevent build up of organic deposits including uric acid deposits and scale. Such cleaning products include aerobic, spore-forming bacterial strains belonging to the genus Bacillus. This product is currently provided by Cleveland Biotech Ltd under the trade name Clearinate®. The product is suitable for use in hospitals, hotels, schools, restaurants, public buildings, offices and nursing homes.
Another example is an existing hydrocarbons degrading product, including selected, naturally occurring Hazard Group 1 micro-organisms to degrade hydrocarbons and surfactants to aid the degradation process. This product is currently provided by Cleveland Biotech Ltd. The product is suitable for degrading petroleum hydrocarbons and can be used in treatment plants receiving effluents from oil refineries. Crude oil can contain in excess of 40% aliphatic compounds varying in size from simple alkanes to long chain molecules such as the C25-C35 alkanes. The greater the chain length and the amount of branching the more resistant the compound is to microbial degradation. The product can degrade such recalcitrant compounds. The product is also suitable for sludge farming and land remediation applications.
Therefore, the use of bacteria as an active ingredient in cleaning compositions is known as exemplified in the above examples.
However, there is still a continuing need for more effective products that can be used in domestic, public and industrial environments such as hospitals, hotels, schools, restaurants, public buildings, offices and nursing homes for cleaning hard or soft surfaces.